This invention relates to a photographic printing method which can obtain identification information on frames of an original film such as a sheet of negative film of which images are being printed in order to corelate imaged frames with photographic paper to be printed.
It is necessary to precisely position imaged frames of an original film on an optical frame in photographic printing systems in order to appropriately print images in a frame of the original film on a sheet of photographic paper. In the prior art, the original film is notched on the side and the notched portions are detected by an optical sensor to position it in a proper relation especially in the case of 110 type size or 126 type size where frames and perforations can be corresponded in 1:1 positional relation. However, the notches should be made precisely at right positions to frames, requiring formidable efforts. The frames can be positioned by constantly advancing the original film by a constant distance, but this method is detrimental as deviations from the right positions tend to accumulate and deteriorate the precision.
In the conventional photographic printing method, the correspondence between images in a frame of the original film and in a printed sheet of the photographic paper is not clearly defined. This presents problems particularly when the images in adjacent frames are similar as it is extremely difficult to distinguish one printed sheet from another when reprinting of a particular frame is required for make-over in the laboratory or when customers later want extra prints. Further, while images of the frames are being printed at the laboratory, it is extremely difficult in the prior art to read the frame numbers with eyes because of the masks present around a negative film carrier to thereby often cause mistakes and confusion. A wrong frame sometimes is printed thus wasting time and the photographic paper. Attempts have been made to record numbers corresponding to the frames of the original film on the photographic paper, but they have not yet been put into practice as detection and identification are difficult in the case of size of 135 type and those other than the case like 110 or 126 type size where the frame numbers attached in latent image correspond to perforations in 1:1 positional relation.